docstr: Tests numerical array input and output. 
docstr_tok: ["Tests","numerical","array","input","and","output","."]
code: def test_0_num_array(self):
      """Tests numerical array input and output."""
      # task: learn to emit next `arr_len` numbers given any numerical array input of length `arr_len`
      df = pd.DataFrame()
      arr_len = 4
      df["input"] = [
          [row + i for i in range(arr_len)] for row in range(200)
      ]
      df["output"] = [
          [row + i + arr_len for i in range(arr_len)]
          for row in range(200)
      ]
      self._test_array(df)
  
file_path: lightwood/tests/integration/advanced/test_array.py
imports: import unittest
  import numpy
  import pandas
  from lightwood.api.types import ProblemDefinition
  from lightwood.api.high_level import json_ai_from_problem, code_from_json_ai, predictor_from_code, predictor_from_problem
label_desc: Use image node_id 2 for calling the TestArrayTarget obj's underlying member method code with example usage: obj.test_0_num_array() without return types